<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>背面滤镜效果</title>
    <style>
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        
        body {
            width: 100%;
            background-image: url("https://picsum.photos/200/300");
            background-size: cover;
            background-attachment: fixed;
            background-repeat: no-repeat;
            /* backdrop-filter: brightness(110%); */
        }
        
        .contain {
            width: 100%;
            height: 100vh;
            backdrop-filter: grayscale(100%);
            transition: all 1s;
        }
        
        body:hover .contain {
            width: 0;
        }
    </style>
</head>

<body>
    <div class="contain"></div>
</body>

</html>
